This invention relates generally to a single lever control assembly for controlling a machine and more particularly to a control shift pattern joint.
Single lever control assemblies of the type known for controlling a machine typically comprise two U-shaped members each having a base and parallel legs extending along spaced longitudinal axes from the base to respective distal ends, a lever supported by one of the U-shaped members, and a pivot block interconnecting the parallel legs. Typically, the range of motion of a single lever control assembly includes a plus pattern and 360xc2x0 rotation, i.e., a swiveling motion.
The pivot block allows the U-shaped members to rotate relative to one another about transverse first and second axes to obtain the plus pattern. In other words, the parallel legs of the first U-shaped member rotate about the first axis when the legs of the first U-shaped member move between the parallel legs of the second U-shaped member. Also, the parallel legs of the first U-shaped member rotate about the second axis when the parallel legs of the first U-shaped member move about the legs of the second U-shaped member. The 360xc2x0 of rotation occur because all the legs of the U-shaped members terminate within a radius of clearance about the axes.
Typically, single lever control assemblies rotate in a plus pattern and in a 360xc2x0 pattern when viewed from above the single lever control assembly. Specific functions are activated and deactivated by moving the single lever control assembly to certain positions. Generally, a specific function is activated at each endpoint of the plus pattern. Two functions can be activated simultaneously by rotating the single lever control about the 360xc2x0 pattern to the midpoint position between the two desired functions.
A disadvantage of using this type of single lever control assembly is that additional components need to be added to limit the range of motion of the lever assembly. Typically, a plate is used to limit the range of motion. For instance, the plate could be either flat or rounded and is placed over the single lever control assembly. Each plate includes a cutout portion or slot in the areas where movement of the single control lever is allowed or desired. One example of such an apparatus is disclosed in U.S. Pat. No. 4,133,251. In that example, the lever is movable laterally in two generally perpendicular directions via a slotted gate pattern.
Another disadvantage of this type of single lever control assembly is that there is an additional expense in manufacturing the plates. Yet another disadvantage is the time required to properly install such a plate. Finally, there is always the possibility that the plate will slip out of position resulting in unrestricted movement of the single lever control.
Therefore, it is desirable to limit the 360xc2x0 motion of the single lever control assembly without requiring extra structural elements. The present invention is directed to overcome one or more of the problems as set forth above.
The invention relates to a single lever control assembly for controlling a machine. The single lever control comprises two U-shaped members each having a base and supporting spaced parallel legs, a lever connected to one of the U-shaped members, and a pivot block interconnecting the parallel legs of the two U-shaped members. The single lever control assembly is characterized by at least one of the legs of one of the U-shaped members having a projection engaging one of the parallel legs of the other U-shaped member to limit rotation.